Be sure you are using only Janome bobbins. Some bobbins on the market say they can be used in the Janome. They can't. Janome's bobbin works off a "floating magnet". The "universal" bobbins can be off just a smidge, but cause problems. Also if you do not have your thread firmly in the take up eye, you may have a problem. Also be sure your bobbin is in the correct direction (The thread should form the letter P before you put it in). Hope this helps.